Method of and apparatus for translating electrical variations.



P. C. HEWITT. I

METHODOF AND APPARATUS FOR TBANSLATING ELECTRICAL VARIATIONS.

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INVENTOR WIT/158858 a,

P. C. HEWITT.

METHOD OF AND APPARATUS FOR TRANSLATING E LECTRICAL VARIATIONS.

APPLICATHN FILED MAY 15. 1915.

1 62 49 1 Patented Apr. 9 1918.

2 SHEETS-SHEET 2.

WITNESSES INVENTUR I BY 7 W 9? 1 MAT/VINE) shape,

Y and the initial density UNITED STATES PATENT OFFICE.

PETER COOPER HEWITT, OF RINGWOOD MANOR, NEW JEIBiSEYy-ASSIGE'OR TOCOOPER. HEWITT ELECTRIC COMPANY, 0E HOBOKEN, NEW JERSEY, A CORPORATIONOF NEW JERSEY.

METHOD OF AND APPARATUS Eon. TRANSLATING ELECTRICAL VARIATIONS.

Specification of Letters Patent.

Patented Apr, 9, 1918} Original application filed March 30, 1907, SerialNo. 365,597. Divided and this application filed May 15,

1915. Serial No.28,435.

To all whom it may concern:

Be it known that I, PETER CooPER HEWITT, a citizen of the United States,and

resident of Ringwood Manor, in the county of Passaic and State of NewJersey, have invented certain new and useful Improvements in Methods ofand Apparatus for Translating Electrical Variations, of which thefollowing is a specification.

My present invention involves the discovery of certain phenomenadeveloped by the flow of electric current through a gas ;or vapor, andit particularly concerns the utilization of such phenomena in connection.with electrical variations of all kinds and for various purposes. I

It is useful in connection with very rapid and very feeble electricalvariations, and is particularly adapted to translate variations ofpotential. When used for detecting the oscillations in the receivingcircuit of a space telegraph or telephone system, the resultsdemonstrate extreme sensitiveness, re-

liability and durability.

My invention contemplates the employ ment of one or more special orauxiliary terminals, or electrodes, in operative relation to a gas orvapor carrying current, said current being supplied to thegas'independently of such auxiliary terminal or terminals.

The geometrical characteristics of the conducting vapor may bedetermined by the size, etc., of a containing vessel and by the size andposition of electrodes therein.

The electrical characteristics of the gas .or a

vapor are dependent upon the geometrical characteristics, upon the kindand purity of the gas or vapor, upon the nature and material of theelectrodes, of the vapor. The density of the vapor depends upon thetemperature and pressure,

ture during operation are. dependent upon the ratio of heat generationto heat radiation. The internal heat generatlon is dependent upon theabove mentioned electrical are sensitive to magnetic action.

and upon the density of a given vapor 1I1 characteristics'and upon theamount of current flowing in the vapor device. The heat radiation isdependent upon the heat radiatmg area and. the temperature of thesurround'ngs. Hence, in the operation of a vapor evice having givengeometrical and electrical characteristicsof construction, the densityof thevapor is controllable by regulating current flow, heat radiatingarea, and

temperature of the surroundings.

The reactions attending passage of current in a conducting gas or vapormaybe subdivided into three definite classes; (1) reactions at and nearthe positive electrode or anode; (2) reactions in the gas or vaporitself; and (3) reactions at and adjacent the negative electrode, orcathode, including reactions at the junction of the negative dark spacewith the vapor carrying current from the main positive electrode,

The separate phenomenaof which the reactions at the positive electrodeor anode are made up, are numerous, and are chiefly modified by theposition,size, and physical state of the anode; and by the purity,density, and kind of gas; and also by current density in the gas.Certain of them One of the visible reactions of the positive electrodeor anode, is a luminous ball or bush which is very sensitive to magneticaction and which tends to be a sourceof variation. At low densities itis very sensitive tomagnetic action. a

The reactions in the conducting vapor itself and modifications thereof,independent of the reactions near the electrodes, have been broadlystated by me. They may be modified by a magnet, especially at lowdensities. The reactions Yof the vapor column are normaly stable, andfor purposes of this invention, its length, the kind of gas, the gasdensity, and the current density are chief modifying factorsv to beconsidered and controlled; Y The phenomena at the negative electrode arenumerous, and include two distinct classes; one class being those foundat the negative electrode when it is in its primary condition, before ithas been changed to I What has been termed by me its low resistance orbroken down state, and another class beingthose which existafter thenegative electrode has attained the low resistance stat-e. lit ischaracteristic of the first mentioned class that on subjecting thenegative electrode in the primary condition, to sufficient electricalstress, a certain point is reached where a leakage current may beobserved under certain conditions. A modified leakage current flowingunder low stress is manifest when said electrode is present in, acurrent carrying vapor having suflicient current density. The oppositionor apparent resistance to this leakage current, is modified by thesurface area of the electrode, and by the current density in the vaporadjacentthereto, and it varies, in ways peculiar to itself with thenature, purity and the density of the vapor, and with the nature andcondition of the electrode. It varies with the temperature of thenegative electrode, and if this temperature be increased toincandescence, this resistance then reaches or comes near its minimumlimit. After the last state of resistance in the primary condition hasbeen reached, if the temperature of the electrode be increased to such apoint as to bring about "a physical or chemical change of state of theelectrode, while current, with suficient backing, is passing into saidelec trode, the reactions will change to those of the second class;namely, those attendant upon the broken down state of resistance, andthe reactions of the negative electrode. will then be measured by a lessdrop in potential. It is often desirable that the drop over the deviceshould be as small as possible and in such case this latter state shouldserve best. This broken down state of the negative electrode may beattained by various expedients now well known in the art.

Accompanying this change are thevisible phenomena of the negative flameto which I have before called attention. The visible phenomena consistof a bright spot on the negative electrode with a flame apparentlyhovering over this spot. The peculiar haracteristic of this flame isthat it ten s to lie'in' and along the magnetic lines of force, ratherthan to be twisted or distorted by them, as is usual to current passing.It tends normally to project itself perpendicularly from the surface ofthe electrode. A magnet may be used to modify or adjust the conditionsat the negative electrode. The bright spot tends to locate itself at ameniscus of an irregularity on anelectrode. The flame itself issurrounded by a dark space and when the flame is in normal position in aright line with the vapor column, the top of the flame usually marks theboundary of the dark space where it joins the luminous positive columnof conducting vapor coming from the positive electrode.

nacaeei The flame is very sensitive to electrical variations, and suchvariations may be ob served when looking at it. Its reactions -may alsobe varied by a magnetic field and its reactions may be made usable inthis way. When the positive electrode is ar-' ranged at comparativelyshort distances from the negative electrode as, for instance, whenlocated within the dark space, there may be no luminous positive column,and the reactions at the positive are modified at certain distances fromthe cathode and may be rendered practically unnoticeable. The positivebush reaction may be' practically eliminated by these means. Thelengthof the vapor column is decreased so that the total voltage dropacross the device is decreased, and the drop due to the positive bushmay be seriously modified it not altogether eliminated. Many of theabove described reactions are modified by rapid electrical variationsand are useful in connection with them.

In the practice of my invention T expose.

within the vapor device, supplied with current through main electrodes,a separate terminal ortwo or more terminals operatively associated witha telephone or other indicat- 'ing instrument and with a source ofvariaterminal of this type, seem to vary with the charge in the body ofthe vapor, particularly in the region immediately adjacent suchauxiliary terminal. The current density in the vapor varies with thetotal amount of current flow between the main electrodes and also withthe relative position or location of the auxiliaryterminal with reference to the main electrodes and the current path between saidelectrodes. Hence, for given conditions, the proper current density orcharge of the vapor adjacent an auxiliary terminal, may be attained byadjusting or arranging the auxiliary terminal nearer to or farther fromthe main electrodes and the path between them, or, where the auxiliaryterminal is already fixed in a suitable position, by increasing ordecreasing the amount of current flowing between the main electrodes.The latter expedient) will usually have the eflect of changing thedensity and nal will have .an effect somewhat analogous to increase ofcharge or current density in the body of vapor adjacent thereto.

By increasing the main current when re- 5 ceiving even faint signals,the volume of the signal may be amplified in many arrangements of thisdevlce, and this may be continued up to the point where they begin to beobscured by other variations developed.

\Vhatever type of device be employed for maintaining the supply ofcurrent in the vapor, such supply should be independent "of theauxiliary electrode used for detecting purposes. An auxiliary electrode,because 1'5 of its position or electrical connections, may

have-a tendency to be a positive or a negative electrode with referenceto thevapor,

or, being maintained at a neutral point, as by a source ofeounter-electromotive force, or by a condenser which may be used assuch, it may under certain conditions tend to act as either, oralternately,-as both. For some purposes it is preferable that it bearranged so as normally to have no current flowing either from or to it,except such currents as are the result of the action of the electricalvariations to be detected, and in case it is desired that the deviceshould have a rectifying action, the auxiliary electrode should tend tooppose a prohibitive barrier to the passage of current from the vaporinto it. This action seems to be more complete when the current flow inthe vapor adjacent to it is at or near a minimum and its surface area isnot too great.

The reactions at the positive electrode are normally in an unstablestate and. give rise to rapid electric variations, which when heard in atelephone are rumbling, rattling,

cracking sounds, and may, under certain conditions, produce clearmusical notes. One means of rendering the reactions at the main positiveelectrode substantially stable, is to bring such main positive electrodein close proximity to the main negative electrode. In such case, thevisible phenomena at the main positive electrode and the voltage drop,are modified and largely suppressed, and the attendant reactions may beso rendered practically noiseless to a telephone at an auxiliaryelectrode.

The size of the positive electrode is im portant with reference to theheating effect on it and also with respect to the bush reaction, and formost purposes it shouldbe'of sufficient area to pass the desired maximumcurrent without becoming unduly overheated but it should not be'toolarge on account of the bush reaction. It may be designed to be highlyheated and its temperature may be made to affect the reactions at thenegative electrode, as well as its own.

The vapor column, considered by itself,

rarely presents any sources of irregular or detrimental electricalvariation. It is desirable to use means to-maintain theeurrent the vapornormally constant and unlform 1n quantity and in distribution.-

device. The desired direction and distribution of the lines of force'ofthe field may be established by proper design and location of a singlemagnet, or a plurality of magnets may be used to establish a resultantfield. With a ring positive electrode, it is usually desirable to havethe lines of force somewhere about 45 degrees from the normal directionof the negative electrode flame and with a disk positive electrodeapproximately parallel with such direction.

In all forms shown herein the conducting gas or vapor is inclosed in asuitable container preferably having three or more electrodes. Theelectrical reactions at the various electrodes and in the conducting'medium may be thus caused and controlled as desired, to enable thedevelopment of suitable reactions within the medium itself for thedesired purposes and to make possible the modification and control ofthe reactions. The temperature and density of the gas or vapor may becontrolled in any desired way, as by determining the area anddisposition of the outer radiating surfaces of the container or by theuse of suitable 6X- pedients for increasing or decreasing the heatabsorbing or heat imparting power of the surroundings.

In all of the forms shown herein, the conducting medium is referred toas a gas or vapor medium contained between electrodes in a hermeticallysealed vessel, but similar circuit connections may be made serv- 11aiceable in connection with other mediums having similar reactions. Apure gas is preferable, however, since it tends to insure uniformity ofthe reactions and I prefer to use a monatoniic gassuch as is afforded bymercury or mercury vapor in a hermetically sealed vessel or container.The container and any solid electrodes therein, are preferably of suchmaterial as not to yield gases under the conditions ofi operation. Themethods of cleansing and evacuating such devices by washing with mercuryvapor and exhausting the same while subjected to the action of heat andof the electric current, arenow well known in the art.

A starting band of the type well known in the art may be applied at amain negative electrode, as at C or an auxiliary electrode,

- as at C and may be used according to the practices well known in theart, or may be rying current supplied to the medium independently of theauxiliary terminal. In general the eircuits'whose reactions are to eutilized, should include differently conducting media afl'ordingvariable electrical, reactions of various classes, such as transitionresistances etc. I prefer a true conductor of the first class, such-asordinary conducting metals, and also a conductor of janother class ofconductivity as, for inemployed to maintain normal current flow stance,one which is adapted to pass vcurrent after the manner of electrolytesor conducting fluids such as gases or vapors. A suitable source felectromotive force should be in the circuit of the fluid medium, saidcurrentflow being preferably of relatively large quantity and lowvoltage. The indicator circuit parallel circuit including a part only ofthe fluid medium of-said first mentioned circuit.

The source of variations to tie-translated may be a circuit of eitherforced variations .or oscillatory variations and maybe an open circuit,connected to ground or. a. capacity, or not, as desired. vA closedcircuit of either Y forced variations or oscillatory variations may beappliedto advantage'or. any of the arrangements shown in each'iand allof the 'figures of the drawings byfconnectinig the. two sides of suchclosedcircuit inthesame' waythat the aerials S and ground G re-j areconnected, or in any; other do spectively sired way, all as will be wellunderstoodby 7 those skilled in the art.

l have specifically shown and described herein only a few of thetypicalandv ole-j] sirable ways of arranging the serial, indi: eating anddirect current'supply circuits. From these it will be evident to oneskilled in the art that my vapor devicev is so sensi tive that thevariations to'be detected or; translated can hardly be applied to-thesame in such manneras not to produce some efiect on the internalreactlons and that those reactions will produce more or less pronouncedsensible effects in the indicator whenever the latter is applied to thevapor device in such manner that, impulses, direct currents, ordisplacement currents may through in response to potent al variations.The instrument should be desied or 10- cated so as not tobe injured bythe amperage of such current flow, and, in general,

should be lateral or. branch or flow there 7 meager it is preferable toarrange the indicator and variation circuits in such manner that thevariations to be detected may pass to the vapor device without beingimpeded or choked out by the indicator.

This is accomplished (by bringing the aerial receiving conductor orother desired source of variations, into operative relation to the vapordevice by connecting it directly to one or more of the auxiliaryelectrodes, or by connecting it to a capacity area arranged inelectrostatic relation to an auxiliary electrode or to the vapor pathbetween it and the main electrodes. This may be done by employing acapacity'area in the form of a metal or tinfoil plate a foot or so indiameter, which is preferably located very close to the container, butit may be located some inches or even some feet away.

'Such' sheet or plate'is illustrated in my apas based on such embodimentof my invention, are contained in said application. In this applicationTclaim the method and also certain special devices, combinations andelements not specifically claimed in said prior application, as forinstance the capacity areaconsistingof a conducting band encircling thedevice adjacent an auxiliary electrode, in a manner analogous to thesocalled starting band which is well-known in the art .as a meansforelectrostatically afi'ecting the main negative electrode of mercuryvapor devices for starting flow of main current between the mainelectrodes.

7 In the accompanying drawing the container is shown in vertical sectionwith the circuit connections thereof diagrammatically indicated,' the,figures correspond respectively-to F1gures2, 4,12,15,21 and 22 ofmy saidprior application." The means for applying variations is shown aselectro- "stati'cally" associated with the other elements"oftheapparatus,but-it will beobviousthat so far as concerns a certainaspects of thexin- 'ventions, the variations may be conductivelyapplied.

Fig. lisa, view showing the electrostatic "band encircling an auxiliaryelectrode located between widely separated main elec-.

trodes, the negative electrode being pro- Mil vided withmeans forrendering more stable the reactions thereat.

Fig. 2 shows the aux1liaryelectrodeat the top of the container and the 7positive electrode arranged close to thenetgative elee;

'trode in such manner as to rendrirmore stablethe reactions at thepositiveelectrode;

Fig. 3 shows an arrangement in which thereare two ring electrodesadjacent to the negative electrode, one of them used as a main positivesuitable regulatin electrode and the other used as an auxiliaryelectrode in connection with a second auxiliary electrode on the top ofthe container.

Fig. 4 shows a container substantially the same as in Flig. 2,associated with a typical indicator circuit.

Fig. 5 shows a similar container but having the auxiliary electrode inthe form of a plate and associated with another typical receivingcircuit. In this form the main positive electrode is adapted to heat aprojection from the negative electrode.

Fig. 6 is a detailed view showing a modified arrangement may be used inthe container of the preceding figures.

Fig. 7 illustrates a vapor device associated with a magnetic field andarranged in shunt to the condenser of a close tuned or resonant circuit,inductively associated with a primary source of variations.

In various of the figures of the drawings, electrodes of thin materialhaving various outlines, are shown as viewed from a point above theplanes of said electrodes, in order to show the structure more clearly.While any one of more of these electrodes may be arranged at various,similar or different angles, it is to be understood that theseelectrodes may be and preferably are arranged with their fiat surfaceslying in planes at right angles to the axis of the vapor device. Ineither case the device is preferably normally operated in a verticalposition, but may be and frequently is operated in a tilted position asdesired, in order to vary internal conditions for particular purposes orconditions.

In the various figures of the drawings, the specific devices embodyingmy invention comprise main positive and negative electrodes, one or moreauxiliary electrodes, and a' su table container. The main electrodes aresupplied with current from a suitable source, preferably a directcurrent source, indicated in the drawings as a storage battery. Thissupply circuit is provided with devices, including preferably an adjustale ohmic resistance and an inductance which is also preferablyadjustable. The ohmic resistance and the inductance may be more or lessembodied in thesame device, but are preferably-sep arate. Suitablereceiving and indicating circuitsare operatively associated with theauxiliary electrode.

Like parts have reference characters on the various fi been indicated bylike res wherever this is possible without lia ility to cause confusion.

. Referring more particularly to Fig. 1, the positive electrode 1 may beany known or desired material suitable. for the purpose, such as iron,platinum, carbon, or other conof main electrodes which I 7 height.

ducting material. The particular cup shaped electrode shown in this andother figures, is preferably of the same material, size and shape as thepositive electrode now in general use in the Cooper-Hewitt lamps.

The negative electrode 2 consists of a body of conducting liquidpreferably of mercury. erably a solid conductor of iron, platinum,carbon, or other suitable material. The container 4 is preferably ofglass, preferably hermetically sealed and preferably having a highvacuum when cold. It may be of any suitable or desired size, and may beconveniently made about 2-1/2 to 3 inches in diameter and about 5 ormore inches in A device of such diameter and 7 inches in height willhave a current carrying capacity through the main electrodes up to 4 or5 amperes at pressures of, say, 7 to 25 .volts, and will have ampleheat-radiating area.

The source of current supply is shown at 8, an adjustable resistance at9, and an adjustable inductance at 10.- The supply cir cuit' is thuscapable of regulationfor purposes of controlling the amperage throughthe lamp and for steadying the same to normally uniform values.

The auxiliary terminal 3 is sensitive to the electrical variations to bedetected and these are operatively applied to the device from anysuitable source of variation, as, for instance, a receiving wire S of aspace telegraph or telephone system connected directly to the auxiliaryterminal or brought in proximity to the device as by connecting it tothe bend or collar C arranged adjacent thereto. It will be understoodthat the variations to be utilized, may be from other sources and may beof comparatively low frequency and greater amperage. Where thevariations to be utilized are feeble or rapid, it is desirable toconnect the supply wire S in electrostatic relation to the auxiliaryelectrode 3 so that there shall be little capacity or impedance in thesupply circuit leading to the auxiliary electrode. The detecting circuitis preferably arranged to to the main positive or negative electrode orin a multiplicity of ways hereafter more fully referred to. In Fig. 1 itis shown connected to a capacity area G which for space signalingpurposes need not be very The auxiliary electrode 3 is preflarge. Aground connection-C is sometimes desirable, but not always necessary,and may be made by connection from a main electrode as in Fig. 3, asdesired.

In a vapor device of the kind shown in Fig. 1, any internally or1g1nateddisturbing variations at the main electrodes, due to the passage of thebattery current, W111 be manifest at the auxiliary electrode and tend toobscure its action when minute variations are to be detected. Hence inFig. 1 I show the device provided with one of the various possible meansfor lessening the 1nternally originated disturbing variations, byrenderingthe reactions at the main negatlve electrode more stable. Thisresult 1s accomplished by arranging a projection 12 extending above thesurface of the mercury 2 and wetted thereby, after the mannerhereinbefore referred to. A platlnum wire projecting a short distanceand having a diam-' eter of .045 inch, serves well for this purpose, forcurrents of from 1-1/4 to 2-1/2 amperes or evenmore.

Fig. 2 represents. a similar vapor device having the reactions at thenegative electrode rendered stable in the manner just described, andembodying also a means for rendering stable the reactions at thepositive electrode. In this form the positive electrode 11 is broughtinto close proximity to the negative electrode and arranged in the formof a ring symmetrically surrounding the projection 12 of the negativeelectrode, above and preferably parallel with the surface of the mercury2 and preferably slightly above said projection. If the ring is used inthe form of a flat disk of iron 1-1/8 inches in external diameter and1/4 inch or less in internal diameter, it will pass 2-1/2 to 3 amperesof current without becoming unduly heated.

The internal diameter of the ring should not be too great with respectto its distance from the projection 12, for otherwise there may be atendency to unstable reactions giving rise to disturbing fluctuations.Ring electrodes of the above specified sizes, however, carrying currentsas described, are very.

suitable for the purpose, but this electrode may be varied in size andshape and may be. a disk or other shape.

A'convenient method of determining or adjusting the distance of such a'positive electrode from the surface of the mercury consists in providingthe container with 'a pocket 15. adapted to contain an extra supplyofmercury 16. In such a device the" desired amount 0 mercury may be pouredor. from the negative electrode into the pocket, or vice versa.

conveniently efiected by shaking the device so that the mercury of thenegative electrode acaeei tive electrode, thereby making and breaking abridge.

With the above described. arrangements, the visible phenomena at themain positive electrode and its resistance are modified and largelysuppressed and the attendant disturbing reactions are made practicallyunnoticeable so far as concerns their efi'ects at the auxiliaryelectrode and in the indicator connected thereto. "The device maybeoperated at a lower potential than that of F 1g. 1 and it has a muchgreater current capacity, the latter being limited, in practice, mainlyby the size and fusibility of the positive electrode.

The heating efi'ect at the positive electrode is less as the surface ofthe positive electrode is increased, and this arrangement may be used tocarry current up to 5 amperes at a voltage of 7 to 10 or 12 volts,depending upon the characteristics of the particular device. Theoperation of this form of device,

under varying conditions, seems to vary with the position of thepositive electrode with respect to the negative electrode, particularlyfor positions varying from barely out of contact with the surface of themercury to, say, 5/8 inch or more from the surface of the mercury.

In this case also, the wireless or other source of variations isconnected directly to the electrostatic band adjacent the auxiliaryterminal. In this figure, as also in Figs. 3, 4 and 7, the upper cupshaped terminal is used asan auxiliary electrode but, as in the case ofFig. 1, the electrostatic band or strip is located so as to inclose theactive part of lizihpdelectrode in an encircling electrostatic In Fig. 3there are two ring electrodes 31, 32 located one above the other. Thereis also a cup shaped electrode 13'at the top. Either one of the ringelectrodes or the cup shaped electrode may be used as the main positiveor as auxiliary electrode or electrodes. 7

When the upper ring-electrode 32, is not used as a main electrode, itappears to serve some useful purpose with reference to the reactionsoccurring at the main electrodes. One apparent effect is that it tendsto preventadherent deposits on the walls of the container, whichotherwise frequently occur and which appear to be caused by exfoliationsfrom the trode.

In this figure the indicator connection is from the upper cup shapedauxiliary electrode 13, to the lower ring electrode 31, f which islocated in the dark space between, In this form of device the startingmay be and adjacent to. the main electrode, the upper ring electrode 32being used as a point 12 of the negative elec main positive electrode.The indicator is located in a circuit connected between this 'ations areall substantially as in Fig. In Fig. 4, however, the indlcatrng circuitisfrom the auxiliary cup shaped electrode at the top of the container,through the indi-' cating device to the negative electrode 2, as shown.The indicator R may be an electromagnetic telephone receiver havingsufficient impedance for the partlcular purpose 1n view, for instance,100 to 2000 ohms resistance.

In Fig. 4 the electromotive force across the indicator circuit from theauxiliary terminal to the main negative electrode is more or lesscounter-balanced, or if desired, overbalanced by the potentiometer 18shown. The latter may be adjusted to cause slight current fiow to orfrom the auxiliary electrode, and this device may be usedin connec 1OI1with the other devices and circuits shown herein.

ig. 6 shows a form of device wherein there may be special heatingactionof the positive electrode 11" on the negative electrode when thepositive electrode is so designed with respect to the current flowingtherethrough as to be highly heated. To

this end the positive electrode is made small,

so as to become heated by the passage of current from it, and isconcentrically arranged around a projection 12 from the negativeelectrode, which it tends to heat,

this projection tending to render stable the negative electrodereactions at its base. Such a positive elect-rode being constructed ofplatinum wire .057 inches in diameter and Wound in a helix, having aninside diameter of 1/4 inch and being of two turns, will become heatedwith 1 ampere passing, and will work with 1-1/2 amperes, the bottom ofthe helix being-substantially 1/8 inch from the level of the mercury.

In Fig. 5 the vapor device is shown with connections to a receivingcircuit which may be useful with other forms of the device. Thereceiving conductor S is shown tuned as at 47 to a quarter wave lengthand the lateral conductor 45 leading to the electrode 13 of the vapordevice is also tuned as at 46 to the same frequency. The groundconnection G may be adjustably connected to v the coil 46, 47, 46, as at48, and when such ground is used the circuit G, 48, 47, S will be theelectrical equivalent of the circuit G, 48, 46, 45, 13, so that therewill be a crest ofpotential at 13. 7

In Fig. 7 the vapor device issliown as connected through a lateralconductor 54 with a closed tuned or resonant circuit, prefe crably tunedto the frequency of the received energy to be detected by means of'a sutableadjustable inductance 51 and an adjust-able condenser 52. Thisclosed tuned circuit is associated by means of a transformer 53 with areceiving wire S, and the parts may be, all designed and operated inaccordance with any of the principles well known in the art. The lateralconductor is shown adjusted as at 55 tothe quarter Wave length of thereceived energy so that there will be a resonant rise of potential at CReferring more particularlyto the arrangement of Fig. 5, if theauxiliary electrode 13 be a circular plate 1-1/4 inches in diameter andits distance from the mercury negative electrode 2 be five inches andthe main positive electrode be a ring of iron 1-1/8 inches outsidediameter having a hole in the centerl/4 to 5/16 inch in diameter and ifit be situated 3/8 of an inch from the surface of the mercury electrode,the container vessel being substantially from 2-1/2 to 3 inches indiameter, and properly exhausted, said vapor device will respond toextremely faint variations. Its sensitiveness may be increased byapproaching an ordinary permanent magnet M somewhat in the manner shownin Fig. 7, the distance varying from close proximity to the device to 18inches or so from it.

A second magnet applied as shown in Fig. 7 may have a beneficial effectin tending to produce a resultant magnetic field wherein the lines offorce lying in the path above 11 and 12 are at an angle of approximately45 degrees from the normal vertical position of the negative electrodeflame.

' The various conditions of electrode size and location, main currentflow, etc., may be so adjusted by trial as to cause a whistling sound ora regular note in the telephone when the magnet is at a suitabledistance from the container; By then adjusting one of the variables,preferably the magnet, the device may be put in a critical Orr-unstablecondition, where faint signals may be indicated by perceptible changesinthe quality, pitch, or intensity of such sound. In some cases thedevice may be put in a con dition where there is little orno perceptiblenote audible and yet the balance is so delicate that the faintestdisturbance, will precipitate the sound of the note, thus giving a.

strong signal where otherwise the effect might be nearly or quiteinaudible.

The circular auxiliary electrode 13 is shown in Fig.' 5 as flattened andarranged in a transverse plane with the flat surface approximatelyequidistant from the path betwecnthe main electrodes, so that almost allof the surface of the electrode exposed to the vapor lies in anapproximately equipotential region of suitable current density.

This arrangement has certain advantages where it is desired to use afine adjustment of counter electromotive force of a potentiometer tosecure the most sensitive condition for feeble signals. One reason forthis is that if the auxiliary-electrode is formed or arranged so thatthe exposed surface thereof extends through regions at materiallydiflerent distances from the path between the main electrodes, differentparts of such exposed surface may lie in regions of materially.different current density. While this latter condition may not beobjectionable for many purposes, it is sometimes found to beunsatisfactory for the finest work in connection with the faintestsignals.

I One probable reason for this is that the condition of most extremesensitiveness of the auxiliary electrode seems to depend upon getting anextremely fine balance of the counter electromotive force -of thepotentiometer against the electrical pressure at the surface of theauxiliary electrode. The latter pressure has for one importantdetermining factor the current density in j the portion of the vapor incontact with the electrode, and it seems to be a fact that if theauxiliary electrode is so formed or arranged that there are materiallydifferent current densities in the vapor adjacent different portions ofits surface, the counter electromotive force of the potentiometer whenset. to a vproper value for the current density adjacent one portion ofthe exposed surface, will be either too great or too small for otherportions where the adjacent cur: rent density is of different value. Onthe other hand, if all portions of the exposed electrode surface areacted upon by vapor v,or substantially the same current density,

the counter eletromotive force may be very accurately adjusted to thatcurrent density, and such adjustment being perfect for one portion ofthe electrode is perfect fo any other portion of the electrode.

Another reason may be that a uniform density or current flow into andout of a considerable area of the electrode may be dem'rable This resultshould be accomplished by the above arrangement of the auxiliaryelectrode, because by it the lengths and resistance ofthe vapor pathfrom different portions of the surface of the electrode, will besubstantially equal.

My experiments show that other things being equal, the perforated plateor ring positive electrode of Fig. 7 seems to give smoother efiects moredirectly proportional to the received variations, whereas animperforated disk seems to give more distorted or disproportionallyamplified indications. This quality of the disk-or imperforate plateseems to preserve the value of the amplified variations more accuratelycation or asymmetric translation of variations of an extremely smallfraction of a volt andof the h ghest frequency, thereby renderingpossible the use of a direct current indicating instrument.

I have found it desirable in order to fully utilize the asymmetricresistance characteristics of the device to so arrange the auxiliaryelectrode that it will act as-anapproximately no resistance pdsitiveelectrode and as a substantially prohibitive negative electrode withrespect tooscillations of the strength which it is desired to translateor detect by such device.

This result may be achieved in connection with any of the typicalcircuits and devices shown herein. Referring for convenience to Fig}. 5,the electrode 13 should be located at such distance from the mainelectrodes ll, 12 that the current flow therefrom and the currentdensity of the vapor adjacent thereto isnear the point where normalinternal variations begin to cause disturbing indications intheinstrument R. In a particular case this distance might be somewherebe tween 4 and 7 inches or, say, about 5 inches. The distance should beand in the case mentioned usually will be, such that the current densityin the vapor adjacent the auxiliary electrode will not be su fiicient toneutralize the opposition or reluctance of such elec trode to act as anegative electrode with respect to impulses of the strength which it isor less. If now the'potentiometer 18 be applied as a source of counterelectromotive force, this drop may be counterbalanced by adjusting thepotentiometer to a pressure of, say, /10 voltin the opposite direction.It is a peculiarity of such device,- however, that in order to suppressthe efiects .of internally originated disturbances in the telephone R,the counter electromotive force should be slightly greater than theoriginal drop, or say somewhere a'bout 75/100 volt, Where the drop wasfound to be 7/10 volt. By still further experimental refinement ofadjustment of this counter electromotive force, the voltage, drop at theauxiliary electrode may be reduced practically to a zero, so that halfWaves or impulses of the smallest fraction of a volt, say, for instance,1/10 volt to 1/100 volt, or less, will pass freely and practicallyunimpeded into the vapor, whereas the half waves or impulses tending torun in the opposite direction will be blocked and prevented from passingfrom the .gas into the electrode 13, so that the effects of thevariations are observable in a direct current instrument. The adjustablepotentiometer thus arranged, is an accurate means for attaining at theelectrode 13, the

conditions which will best serve the purpose of detecting alternatingcurrents by a direct current instrument and yet not give rise to undueinternally originated disturbances which miglilt tend to mask theeffects in the indicator While I have last above described anarrangement of my device which is particularly efiicient for rectifying,it will be understood that the device is so remarkably sensitive in sucha variety of ways that, it will act as a very good detector of feeblevariations such as are characteristic'of'the receiving wires of ordinarycommercial Wireless telegraph systems, even when the ad j ustments aresuch that the asymmetric action is at a minimum. 7

With reference to magnets, it will be understood that the position andnumber of the magnetic lines and their action with respect to thenegative electrode flame and other phenomena, may be varied as desired,

to suit the conditions.

I claim:

1. An apparatus for translating electrical variations comprising atranslating device and a connection therefrom through an electrode to abody of conducting gas or vapor, adapted to be maintained in a lowresistance conducting condition in combination with means forcontinuously maintain:

a ing current in said vapor independently of said electrode, and aconducting band for electrostatically applying variations to saidapparatus, substantially as described. I

2. An apparatus for translating electrical variations comprising atranslating device and a connection therefrom through a true conductorof the first class to. a conducting gas or vapor maintained in-the lowresistance conducting condition in combination with means forcontinuouslymaintaining current'in the gasor vapor independentlyof Saidconnection through said true conductor, and a conducting band forelectrostatically applying variations to said apparatus, substantiallyas described.

normal current flow therein, the positive electrode extending into thedark space adjacent to the negative electrode, together with anencircling band variably charged through said variation connection.

5. An apparatus for translating electrical variations. comprisingindicator, variation and main current supply connections, in combinationwith a gas or vapor: tube provided with electrodes for maintainingnormal current flow therein, the positive electrode extending into thedark space adjacent to the negative electrode, and one of them being ofvaporizable material, together with an encircling band variably chargedthrough said variation connection.

6. An apparatus for translating electrical variations comprisingindicator, variation and main current supply connections, in combinationwith a gas or vapor tube, provided with electrodes for maintainingnormal current flow therein, the positive electrode extending into thedark space adja cent to the negative electrode, the negative electrodebeing of vaporizable material and encircling band variably chargedthrough said variation {connection 7. An apparatus for translatingelectrical variations, comprising an evacuated container,cooperatingelectrodes, circuit connections therefor, and an indicator,operatively associated therewith, in combination with a capacity areaconsisting of an encircling band in inductive relation to saidcontainer, and a source of electrical variations connected to saidcapacity area, for the purpose described.

8. An apparatus for detecting feeble electrical variations comprising ahermetically sealed container having a high vacuum when cold and.provided with main elec trodes, an auxiliary terminal, and a circuittherefrom through an indicator, in combinasealed container having a highvacuum when sisting of an encircling band in inductive relation to saidcontainer, and a main circuit for maintaining current flow through saidmain electrodes of suflicient quantity to maintain the main negativeelectrode in the broken down state, substantially as described.

10. An apparatus for detecting feeble electrical variations comprising ahermetically cold and provided With main electrodes, an auxiliaryterminal, and a circuit therefrom through an indicator, in combinationWith a capacity area consisting of a band mounted upon said container,adjacent said auxiliary electrode, and a main circuit for maintainingcurrent flow through said main eleotrodes independently of saidauxiliary terminal.

11. The method of utilizing the reactions at an electrode in a gas orvapor device supplied with currents independently of said electrode,which method consists in correlating the location of the exposed surfaceof the electrode and the distribution of the independently suppliedcurrent so as to present an approximately prohibitive negative electroderesistance to passage of current from the vapor into said thirdelecmeaaei s. tr de and an approximately minimum re- 51 tfance topassage of currents 1n the op- ,gposlte direction, and applyingelectrical vapassage of current from the vapor into said third electrodeandan approximately minimum resistance to passage of currents in theopposite direction, and applying electrical variations by electrostaticinduction in the region of said electrode and the adjacent vapor,substantially as described.

13. The method of utilizing the reactions at an electrode in a vacuumdevice containing a monatomic gas or vapor suppliedwith currentsindependently of said electrode, which method consists in correlatingthe location of the exposed surface of the electrode and thedistribution of the independently supplied current so as to have itsre-. actions at or near the point Where its opposition to the passage ofnegative current approaches a maximum, and applying electricalvariations by electrostatic induction in the region of said electrodeand the ad jacent vapor, substantially as described.

Signed at New York city, in the county of New York and State of NewYork, this 14th day of May, 1915.

PETER COOPER HEWITT. Witnesses:

' WALTER E. F. BRADLEY, RAYNER M. BEDELL.

